Internal feedback proportional flueric amplifier

ABSTRACT

An internal feedback proportional flueric amplifier which includes a power jet input channel, a left control input channel, a right control input channel, a first output channel and a second output channel. Blunt splitters are provided such that flow from the power jet input channel when entering the interaction region within the amplifier will create internal feedback vortices therein. The effect of the vortices so created is to cause low-pressure areas along the sides of the power jet flow so that when a control signal is applied to one of the control input channels a high-pressure gain, stable, minimum noise amplifier will be obtained.

United States Patent 3,486,520 12/1969 Hyer et a1.

inventors Appl. No.

Filed Patented Assignee INTERNAL FEEDBACK PROPORTIONAL FLUERIC AMPLIFIER 5 Claims, 1 Drawing Fig.

References Cited UNITED STATES PATENTS 3,275,013 9/1966 Colstonmm. 137/815 3,294,103 12/1966 Bowles 137/81.5 3,452,772 7/1969 Zaloudek 137/815 3,474,805 10/1969 Swartz 137/815 X Primary Examiner-William R. Cline Att0rr:eysHarry M. Saragovitz, Edward J. Kelly, Herbert Berl and J. D. Edgerton ABSTRACT: An internal feedback proportional flueric amplifier which includes a power jet input channel, a left control input channel, a right control input channel, a first output channel and a second output channel. Blunt splitters are provided such that flow from the power jet input channel when entering the interaction region within the amplifier will create internal feedback vortices therein. The effect of the vortices so created is to cause low-pressure areas along the sides of the power jet flow so that when a control signal is applied to one of the control input channels a high-pressure gain, stable, minimum noise amplifier will be obtained.

PATENTH] JUL20 as?! WNVENTUHS GARY L HUFFMAN R/CHARD DEADWYLER A TURNEYS BACKGROUND OE THE INVENTION This invention relates generally to flueric amplifiers and more particularly to a proportional flueric amplifier which is capable of producing high-pressure gain because of internal feedback developed therein.

In the past, it has been found that the pressure gain of a proportional flueric amplifier could be increased by the use of external positive feedback. This external positive feedback would be provided by feeding the respective amplifier outputs back to the control inputs on the opposite sides thereof. While the above technique of increasing amplifier gain was found to be somewhat satisfactory, it became apparent that the time delays inherent in an external-feedback-type arrangement would not only decrease the stability of the flueric amplifier, but would increase the noise thereof. Moreover, it was found that a nonlinear gain characteristic curve for a given amplifier input would occur in external-positive-feedback-type arrangement.

One other problem with prior art flueric amplifiers was that when loaded, such for example as by the cascading of several similar amplifier stages, it was found that the effective gain of each stage would decrease thus giving an overall lower cascaded gain.

Additionally, in the past while flueric amplifiers with external positive feedback could be used as an integrating device, this required the placing of external high-impedance flow resistors in the feedback channels thereof so that the time response of the system would become quite long and accordingly, approach an integration time.

SUMMARY OF THE INVENTION Accordingly, one object of the present invention is the provision of a new and improved, proportional flueric amplifier.

Another object of the instant invention is to provide a new and improved proportional flueric amplifier with a higher signal-stage pressure gain than has heretofore existed.

A further object of this invention is the provision of a unique high-gain proportional flueric amplifier having internal feedback inherent therein.

Still another object of the subject invention is to provide a high-gain internal feedback proportional flueric amplifier which is both stable and quiet.

Yet another object of this invention is to provide a new and improved internal feedback proportional flueric amplifier which has minimum feedback delays, such that a linear highgain characteristic curve for a given input signal is provided.

Still another object of this invention is the provision of a new improved internal feedback proportional flueric amplifier the gain of which, in fact, increases when subjected to a loaded condition.

One other object of the instant invention is to provide a new and improved internal feedback proportional flueric amplifier which may be used as an integrating device when the gain is adjusted to a large value without any need for the use of external flow resistors.

Briefly, in accordance with this invention the foregoing and other objects are attained in one aspect by the use of a proportional flueric amplifier which includes blunt splitters on the sides of the amplifier output channels such that when power jet flow enters the amplifier interaction region the blunt splitters will produce an internal positive feedback vortex, the effect of which is to increase the pressure gain of the amplifier.

BRIEF DESCRIPTION OF THE DRAWING A more complete appreciation of the invention and many of the attendant advantages thereof will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying solitary view which illustrates an internal feedback proportional flueric amplifier according to the present invention.

DETAILED DESCRlPTlON OF THE PREFERRED EMBODIMENT Referring now to the drawing, the: proportional flueric amplifier of the present invention is shown as consisting of a conventional power jet input channel w, right control input channel 12, a left control input channel M, a right output channel 16 and a left output channel 118. Fluid flow may be provided to the power jet input channel ill from any desired source, such for example as water, air, gas or the like and will enter the interaction region 20. This fluid flow will then divide with one portion thereof exiting through a right bleed channel 22 into a right vent channel 42 and a right vent 23 and another portion exiting through a left bleed channel 24 into a left vent chamber 44 and a left vent 25, with other portions thereof exiting through right output channel 16 and left output channel 18. Vent chambers 42 and M are bounded by sidewalls 43 and 45 respectively to guide fluid to vents 23 and 25 respectively. The source of flow from the power jet channel 10 will also produce low-pressure regions along the left side 26 and the right side 28 of the jet flow. These low-pressure regions are caused by internal positive feedback vortices 30 and 32 which are respectively produced by the jet flow upon collision thereof with a left blunt splitter 34 and a right blunt splitter 36. Now assuming that a control signal is applied to the left control input channel M, an increased proportion of the jet flow within the interaction region 20 will be directed through the right bleed channel 22, the right vent 23 and the right output channel 116. The effect of this increased jet flow on the right side of the interaction region 20 will [be to still further reduce the pressure along the right side 28 because of the resulting increase in the velocity of vortex 32, which is in turn caused by a greater flow striking the right blunt splitter 36. A pressure differential will now exist across the jet flow area due to the difference in pressure existing along sides 26 and 28 thereof. The effect of this pressure differential will be to further enchance the proportion of jet flow (in the same direction as the control signal) that will enter the right bleed channel 22, the right vent 23 and the right output channel in. Thus, it should be apparent that a much larger deflection of the jet flow to the right side of the interaction region 20 will be produced than would be produced by the control signal itself. This larger deflection will in turn produce a much greater pressure differential across the output channels 116 and lb of the flueric amplifier for the same control input pressure differential and thereby result in a high-pressure gain amplifier without the need of ex temal positive feedback. It should be understood that a similar high-pressure gain amplifier will result if a control signal is applied to the right control input channel 12, instead of the left control input channel M as described above, the delays inherent in an extemal-type feedback arrangement are eliminated and the amplifier stability thereby increased.

In addition, the noise output of the flueric amplifier of the present invention both as an audible: acoustic signal and as fluctuations in the output signal is quite low. This is because the blunt splitters 34 and 36 reduce edge tone oscillations which are normally present in conventional flueric amplifiers and thereby give a resulting lower noise output.

It has also been found that when the internal feedback amplifier of the present invention is utilized for extremely high gain that the time response of the system will be quite long and approximate an integration, thus allowing the amplifier to operate as an integrating device without the requirement of high-impedance external flow resistors as previously required.

One other feature of the present invention is that with the l6 and 18 are used to drive a similar stage in a cascade ar- It should be understood, however that the above dimensions rangement or are partially blocked by the use of flow resistors are given by way of example only and not by way of limitation. or the like, the amplifier gain will in fact increase as opposed Thus, other high-pressure gain amplifiers of any desired size to prior amplifiers which would in fact lose as much as half the may be readily designed in accordance with the described ingain which exists in an unloaded condition. vention.

Also, it has been found that because of internal feedba k Obviously, numerous other modifications and variations of the amplifier of the present invention ill id a li the present invention are possible in the light of the above characteristic gain curve for a given in ut signal. teachings. For example the blunt splitters of the present inven- Referring now again to the solitary FIGURE, it should b tion could be either angled or of curved shape. Such a modifiunder tood that the om t f h lifi f h bj 10 cation will have the disadvantage of slightly reducing the ami mi i important d can ff t h i h r f by plifier gain, but will have the advantage of further reducing d i i h l i i f vonices 30 and 32 and thus the amplifier noise and increasing the stability thereof. It is therelow pressure developed along the sides 26 and 28 of the jet to be f f that within scope of f pp fl For examPlethe setback distance, designated by the an claims, the invention may be practiced otherwise than as rows 38, of the input channels 12 and 14 must be small, of the ally described herein.

order of three times the nozzle width of the power channel 10. what we as new f' des're to be Secured by Letters Increasing the setback width will reduce the amplifier gain, Patent ofthe Ufmed I while decreasing the same will increase the gain. Additionally, A 'i 'f ampl'fier E P decreasing the size of the right bleed flow region 22 and the a power Jet mput channel for 'ssumg Power fluid left bleed flow region 24 will tend to reduce the gain. In fact, lmixacnonfeglonl b. an interaction re ion for receiving said power fluid;

any geometric change that will change the amount of flow that c. comm] channels or deflecting said power fluid;

Will enter the low-pressure areas along the sides 26 and 28 of outpu channels f receiving that portion f Said power the jet flow can influence the gain of the amplifier. Thus, if the fluid which is deflected by Said comm] channels;

( f 23 and are reduced, the gain of the amplifier win 25 e. first and second vent chambers in communication with llkewlse be reducgd- This Occurs Since p bleed flow said interaction region, each of said vent chambers being will now be caused to Produce a back Pressufe which in mm bounded by sidewalls for directing a portion of said power will move the power jet in a direction counter to the centre fl id to atmosphere; d

f. first and second blunt splitters contiguous with said The geomen'y of the amplifier of subject invention can 30 sidewalls and facing said interaction region for deflecting also affect the amount of noise present therein. For example, that portion of said power fluid impinging thereon back the idth of the bleed cha n ls 22 and 24 Sh ul be t 80 that toward said interaction region so as to create internal the flow therethrough will fill the channel walls and attach ositive feedback vortices, said blunt splitters being thereto. Otherwise, low-frequency fluctuations in the flow will located between said output channels and said vent occur and produce pressure signals which could cause noise in chambers.

the amplifier output. Such an adjustment of the width of the 2. A proportional flueric amplifier as in claim 1 wherein said bleed channels 22 and 24 will also provide the proper amount internal positive feedback caused is due to a first vortex and a of negative feedback to maintain amplifier stability and will second vortex being created upon said source of flow striking also minimize the effect of disturbances from outside the amsaid first and said second blunt splitters, the effect being to plifier. Likewise, blocking the vent channels 22 and 24 will create a pressure differential across said source of flow such have the advantageous effect of redu in illation and that upon the application of said control signal a greater hence amplifier noise, but will also have the disadvantage of amount of flow will enter said Output channel on the pp reducing the amplifier gain. side of said control channel then would occur by said control Because of the importance of the dimensions of the amplifialone he ebysaid high-pressure gain is obtained. er of the subject invention, typical values thereof for an exem- A PropomQnal fluenc p as m Glam 2 Where"! Sald plary f rr d e b di are as f ll blunt splitters are curved whereby both the pressure gain and Width of Pow r Jet 10=0,00l 5" noise of said amplifier are reduced. width f Bl d Ch l 22 d 24==() 53" 4. A proportional flueric amplifier as in claim 2 wherein said wid h of output Ch l 16 d 1g=0 5" blunt splitters are angled such that both the pressure gain and Width ofControl Channels 12 and 14=0.0023" Home of said mp s e Length f Blunt splitters 34 and 36:9'010" 5. A proportional fluenc amplifier as in claim 2 wherein said width of Van! Channels 23 and 25:0015 w control input channels are of the order of three times the noz- Comm] sehack width =00045 zle width of said power jet channel. Depth of Amplifier =0.00 l 0--0.0050" 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3593333 Dated y 0, 1971 Inventor(s) Gary L. ROffman and Richard Deadwyler It is certi ied that e rror appears in the above-identified patent and char said Let-.2:

ers Patent are hereby corrected as shown below:

0n the cover page, colilmn 1, line 8, "Navy" should be corrected to read Army The Figure should be corrected to show numerals 42,43,44, and 45 as shown below:

L Signed and sealed this 21st day of March; 1972 (SEAL) Attest:

EDWARD M. FLETCHER,JR.

ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

1. A proportional fluid amplifier comprising: a. a power jet input channel for issuing power fluid into an interaction region; b. an interaction region for receiving said power fluid; c. control channels for deflecting said power fluid; d. output channels for receiving that portion of said power fluid which is deflected by said control channels; e. first and second vent chambers in communication with said interaction region, each of said vent chambers being bounded by sidewalls for directing a portion of said power fluid to atmosphere; and f. first and second blunt splitters contiguous with said sidewalls and facing said interaction region for deflecting that portion of said power fluid impinging thereon back toward said interaction region so as to create internal positive feedback vortices, said blunt splitters being located between said output channels and said vent chambers.
 2. A proportional flueric amplifier as in claim 1 wherein said internal positive feedback caused is due to a first vortex and a second vortex being created upon said source of flow striking said first and said second blunt splitters, the effect being to create a pressure differential across said source of flow such that upon the application of said control signal a greater amount of flow will enter said output channel on the opposite side of said control channel then would occur by said control alone whereby said high-pressure gain is obtained.
 3. A proportional flueric amplifier as in claim 2 wherein said blunt splitters are curved whereby both the pressure gain and noise of said amplifier are reduced.
 4. A proportional flueric amplifier as in claim 2 wherein said blunt splitters are angled such that both the pressure gain and noise of said amplifier are reduced.
 5. A proportional flueric amplifier as in claim 2 wherein said control input channels are of the order of three times the nozzle width of said power jet channel. 